John Ostrom: The man who saved dinosaurs

Saw this on Facebook recently
The following is from an online Yale Alumni Magazine article (link below) by award-winning author, Richard Conniff, July/August 2014.

Preview
“In his book The Riddle of the Dinosaur, science writer John Noble Wilford added that Bakker “was the young Turk whose views could be dismissed by established paleontologists. Ostrom, however, could not be ignored.” Late in 1969, Ostrom took the challenge directly to the North American Paleontological Convention in Chicago, declaring in a speech that there was “impressive, if not compelling” evidence “that many different kinds of ancient reptiles were characterized by mammalian or avian levels of metabolism.” Traditionalists in the audience responded, Bakker later recalled, with “shrieks of horror.” Their dusty museum pieces were threatening to come to life as real animals.”

Figure 1. John Ostrom, from young paleo stud to elderly professorial type.

Figure 1. John Ostrom, as a young paleo stud and as an elder statesman several decades later demonstrating a degree of isometry and allometry during ontogeny.

“Against this false negative, Ostrom laid out the positive evidence, listing more than 20 anatomical similarities between Archaeopteryx and various dinosaurs. It wasn’t just that Ostrom could not be ignored. He was far too thorough and meticulous, and for 30 years too persistent in the face of his critics, for anyone to refute.”

The LRT has been online for only 8 years, so only 22 to go!

“Though one or two holdouts still resist the idea, it is now widely accepted that birds evolved from the group of bipedal theropod dinosaurs”

“The idea that birds are in fact living dinosaurs is so commonplace that the debate has largely turned to the question of why they were the only dinosaurs to survive the mass extinction of 65 million years ago.”

“More significantly, Ostrom lived to see his ideas about the dinosaur origin of birds—and the feathered plumage of dinosaurs—vindicated by a series of remarkable fossils from northeastern China.”

Those should have been unnecessary as Ostrom explains below.

“On Ostrom’s death in 2005, age 77, the Los Angeles Times wrote that he had “almost single-handedly convinced the scientific community that birds are descended from dinosaurs.” “John Ostrom,” the Sunday Times (London) added, “did more than anyone else to make dinosaurs interesting, real, and visceral.”

“When NPR’s All Things Considered marked the occasion by interviewing Ostrom’s first research student, Bob Bakker, the paleontological world held its breath for a moment, recalling the troubled relationship between these two allies in the dinosaur renaissance. But when asked how important Ostrom had been to dinosaur paleontology, Bakker graciously commented: “Nobody was more important.”

In the comments section to the online article,
you can read from Paul Sereno’s epitaph of Ostrom, “He did more than simply point out the great number of similarities between this theropod and the early bird Archaeopteryx. He argued that these similarities were derived. That is, that they were synapomorphies—shared morphology from common ancestry.”

We looked at Ostrom’s frustration with
the slow pace of paleontology earlier. Here it is again.

According to the Hartford Courant (2000), “In 1973, Ostrom broke from the scientific mainstream by reviving a Victorian-era hypothesis (see above) that his colleagues considered far-fetched: Birds, he said, evolved from dinosaurs. And he spent the rest of his career trying to prove it.” With the announcement of the first dinosaurs with feathers from China, Ostrom (then age 73) was in no mood to celebrate. He is quoted as saying, ““I’ve been saying the same damn thing since 1973, `I said, `Look at Archaeopteryx!’” Ostrom was the first scientist to collect physical evidence for the theory. Ostrom provoked a debate that raged for decades. “At first they said, `Oh John, you’re crazy,”’ Ostrom said in 1999.”

On the night Ostrom was to be honored
at the annual convention of the Society of Vertebrate Paleontology, I noticed him walking alone to the proceedings. I took advantage of the coincidence to walk with him. He was gracious enough to allow that. I cannot remember the substance of our conversation. As soon as we got to the building, he was swept up into the celebration as everyone else wanted their own moment with the man who saved dinosaurs.


References

https://pterosaurheresies.wordpress.com/2016/03/16/sometimes-it-takes-the-paleo-crowd-an-epoch-to-accept-new-data/

https://yalealumnimagazine.com/articles/3921-the-man-who-saved-the-dinosaurs?fbclid=IwAR1HMFU7cxeqn-iGd8dtO6nAxsjpERhyTza2AnpkCDz05k9fY3w-63-q4Wc

‘Prehistoric Life – Animated size comparison’ on YouTube

Figure 1. Click to enlarge. Pteranodon scene from Prehistoric Life video from Dane Pavitt. Incredible, excellent video, hearkening back to Giants of Land, Sea & Air - Past & Present (Peters 1986). Just a tweak or two necessary for the included Pteranodon. Extend those metacarpals and elevate that stance!

Figure 1. Click to enlarge. Pteranodon scene from Prehistoric Life video from Dane Pavitt. Incredible, excellent video, hearkening back to Giants of Land, Sea & Air – Past & Present (Peters 1986). Just a tweak or two necessary for the included Pteranodon. Extend those metacarpals and elevate that stance!

Another incredible YouTube video from animator Dane Pavitt!
Click below to view both of them.

I’m just nit-picking here…
In Dane Pavitt’s Pteranodon scene just a tweak or two is necessary to match the otherwise excellent presented data. Elongate those metacarpals and elevate that stance, as shown by the added Pteranodon data (Fig. 2). The small medial fingers, alas, could not contact the substrate (given available data), but this is one instance in which, perhaps, the big wing finger could. More likely Pteranodon was bipedal, only resting on its big wings.

Post-crania Pteranodon

Figure 2. Click to enlarge. Various Pteranodon specimens known from post-crania. Note the yellow box includes one of the largest specimens, but it has an unfused extensor tendon process, which may mean it is a very large Nyctosaurus with fingers.

Remember,
pterosaurs were bipeds originally and often. Typically pterosaur beach-combers and waders made quadrupedal tracks. They had different proportions. We have  bipedal tracks for the germanodactylid ancestors of Pteranodon.

Earlier (March 2016) Dane Pavitt premiered
an incredible march of dinosaurs video (click to view below) now with 17+ million views.

I’m delighted to see these videos
continuing and expanding in action and scope a concept presented in book form over 30 years ago (Peters 1986). I wonder if Dane Pavitt had a copy as a child.

References
Peters D 1986. Giants of Land, Sea & Air – Past & Present. A. Knopf. Click here to view.

Figure 1. The cover of Giants, the book that launched my adult interest in dinosaurs, pterosaurs and everything inbetween.

Figure 3. The cover of Giants, the book that launched my adult interest in dinosaurs, pterosaurs and everything in-between. Click to view and/or download the book.

Looking for a vestigial toe 5 on Jeholosaurus

Jeholosaurus is a small Early Cretaceous sister
to the Late Jurassic Chilesaurus and Late Triassic Daemonosaurus. All three nest as basalmost Ornithischia in the large reptile tree (LRT, 1399 taxa).

Phylogenetic bracketing indicates
a likely pedal digit 5 with a few phalanges should be found on all three taxa. Prior studies failed to reveal it. Current data does not include the pes for Daemonosaurus, nor show the ventral aspect of Chilesaurus, but Jeholosaurus does present the view we’re looking for (Fig. 1). I failed to notice pedal 5 before. I think others have overlooked it as well. Here it is:

Figure 1. Jeholosaurus pes in ventral aspect. DGS colors identify parts of pedal digit 5 disarticulated and broken on the sole of the foot and reconstructed at right.

Figure 1. Jeholosaurus pes in ventral aspect. DGS colors identify parts of pedal digit 5 disarticulated and broken on the sole of the foot and reconstructed at right. This observation is awaiting confirmation or refutation. Phylogenetic bracketing indicates this foot had a pedal digit 5 in vivo.

Finding pedal digit 5 on Jeholosaurus
was made a bit more difficult due to the vestige nature of the digit and its crushed and broken pieces, disarticulated from its traditional alignment lateral to pedal digit 4. This observation based on this photo awaits confirmation or refutation.


References
Han F-L, Barrett PM, Butler RJ and Xu X 2012. Postcranial anatomy of Jeholosaurus shangyuanensis (Dinosauria, Ornithischia) from the Lower Cretaceous Yixian Formation of China. Journal of Vertebrate Paleontology 32 (6): 1370–1395.
Xu X, Wang and You 2000. A primitive ornithopod from the Early Cretaceous Yixian Formation of Liaoning. Vertebrata PalAsiatica 38(4:)318-325.

wiki/Jeholosaurus
wiki/Daemonosaurus

 

 

New book encourages critical thinking in paleontology

Pagnac 2019 brings some fresh views to paleontology courses.
“University dinosaur courses provide an influential venue for developing aptitude beyond knowledge of terrestrial Mesozoic reptiles. Examination of dinosaur paleontology can develop competence in information analysis, perception of flawed arguments, recognition of persuasion techniques, and application of disciplined thought processes.
Three methods for developing critical thought are outlined in this book.
  1. “The first uses dinosaur paleontology to illustrate logical fallacies and flawed arguments.
  2. The second is a method for evaluating primary dinosaur literature by students of any major.
  3. The final example entails critique of dinosaur documentaries based on the appearance of dinosaurs and the disconnect between scientific fact and storytelling techniques.”

Students are owed more than dinosaur facts; lecturers should foster a set of skills that equips students with the tools necessary to be perceptive citizens and science advocates.”

Here at PterosaurHeresies
readers are also provided a set of skills and tools to illustrate logical fallacies and flawed arguments, evaluate and criticize with authority past and present paleo literature and challenge studies flawed by taxon exclusion.

Four questions:

  1. Do paleontologists engage with those critical of their favorite hypotheses?
  2. Do paleontologists ever accept (after rigorous testing) critical thinking that overturns their own pet hypotheses and/or traditional paradigms?
  3. Do paleontologists disrespect critical thinking if it comes from certain sources (ignoring the readily available data while doing so)?
  4. Are paleontologists ever annoyed by the achievements of others?
  5. All of the above?

Take your time in answering these.
Hopefully the Pagnac book will indeed encourage critical thinking. We looked at the lethargy that has always surrounded paleontology here.

References
Pagnac D 2019. Dinosaurs: A Catalyst for Critical Thought Elements of Paleontology

SVP 2018: The clade ‘Ornithoscelida’ tested

Mortimer et al. 2018
reevaluate taxa and scores for the proposed clade ‘Ornithoscelida’ (Baron, Norman and Barrett 2017) and find it less parsimonious than alternatives. The authors, “find hundreds of questionable scores, many characters are correlated with each other, score for multiple variables at once, or are formed in such a way that potential homology is masked.” 

After repairing scores,
the authors report, “none of these experiments supported Ornithoscelida over Saurischia.” Their results show:”that phylogenetic analysis of morphological data is highly vulnerable to typographic errors and other accidental, unsystematic misscores in data matrices; both quantity and quality of scores are important.”

We looked at
the Ornithoscelida hypothesis earlier here, here, here, and here. It is not supported by the large reptile tree (LRT, 1313 taxa, subset Fig. 1), which supports the hypothesis of a Theropoda-Phytodinosauria dichotomy splitting Dinosauria after the Herrerasaurus clade.

Importantly
the outgroup taxa to the Dinosauria must be recovered correctly. At present few to no other studies have included a robust selection of bipedal crocodylomorphs, which nest as the sister group to the Dinosauria in the LRT. Together only Dinosauria and Crocodylomorpha make up the Archosauria in the LRT.

Figure 4. Subset of the LRT focusing on the Phytodinosauria. Three sauropods are added here.

Figure 4. Subset of the LRT focusing on the Phytodinosauria.

Scoring errors
are found in all (yes, all) phylogenetic analyses, including the LRT. One way to ‘eyeball’ whether an analysis is close to recovering actual evolutionary events is to look at every node for a gradual accumulation of derived traits. Key to this ideal is the inclusion of a sufficient number of relevant taxa. The LRT provides a good guide for taxon selection. As it grows larger it becomes a self-healing cladogram where imprecisely nested taxa reveal themselves. Some scores, when corrected, cement relationships. Other scores crack them apart.

References
Baron MG, Norman DB, Barrett PM 2017. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 543:501–506.
Mortimer M, Gardner N, Marjanovic D and Dececchi A 2018. Ornithoscelida, phytodinosauria, saurischia: stesting the effects of miss cores in matrices on basal dinosaur phylogeny. SVP abstracts.

The many faces (and bodies) attributed to Camarasaurus

The genus Camarasaurus is known from several species
These display differences in the shapes of their skulls and post-crania (Fig. 1). Distinct from the bipedal or tripodal Diplodocus we looked at yesterday, the general build of this genus suggests it did not rise from all fours. Rather elevation of the great neck enabled high browsing, though not as high as its sister in the LRT, Brachiosaurus

Figure 1. Camarasaurus AMNH 567.

Figure 1. Camarasaurus lentus AMNH 567. Compare to shorter legged SMA 0002 specimen in figure 2.

Once considered a Camarasaurus,
the short-limbed, big pelvis Cathetosaurus (Fig. 2) is certainly related, but distinct from the other camarasaurs.

Figure 2. The SMA0002 specimen attributed to Camarasaurus.

Figure 2. The SMA0002 specimen attributed to Camarasaurus an/or Cathetosaurus. Note the robust elements and short distal limbs.

Not only are the bodies distinct,
so are the skulls (Fig. 3) assigned to this genus.

Figure 3. Several skulls attributed to Camarasaurus to scale. SMA 0002 is the short-limbed Cathetosaurus. Brachiosaurus appears to be a derived camarasaur.

Figure 3. Several skulls attributed to Camarasaurus to scale. SMA 0002 is the short-limbed Cathetosaurus. Brachiosaurus appears to be a derived camarasaur. We’re looking at the inside of the mandible in the DINO 2580 specimen.

As in many genera
for which several specimens are known, it is always a good idea to start with just one rather complete specimen in phylogenetic analysis. Add others as your interest grows.

References
Gilmore CW 1925. A nearly complete articulated skeleton of Camarasaurus, a saurischian dinosaur from the Dinosaur National Monument, Utah. Memoirs of the Carnegie Museum 10:347-384.
Madsen JH Jr, McIntosh JS, and Berman DS 1995. Skull and atlas-axis complex of the Upper Jurassic sauropod Camarasaurus Cope (Reptilia: Saurischia). Bulletin of Carnegie Museum of Natural History 31:1-115.
McIntosh JS, Miles  CA, Cloward KC and Parker JR 1996. A new nearly complete skeleton of CamarasaurusBulletin of the Gunma Museum of Natural History 1:1-87.
McIntosh JS, Miller WE, Stadtman KL and Gillette DD 1996. The osteology of Camarasaurus lewisi (Jensen, 1988). Brigham Young University Geology Studies 41:73-115.
Tschopp E, Wings O, Frauenfelder T, and Brinkmann W 2015. Articulated bone sets of manus and pedes of Camarasaurus (Sauropoda, Dinosauria). Palaeontologia Electronica 18.2.44A: 1-65.

Diplodocus joins the LRT

There are several ways to measure the tallest dinosaur.
One way is to let the long sauropods, like Diplodocus carnegii (Fig. 1; Marsh 1878; Late Jurassic; 25-32 m long), stand on their hind limbs, like their prosaurod ancestors, balanced by a very long narrow whiplash tail of up to 80 vertebrae. While the neck could not be elevated much beyond horizontal (relative to the dorsal vertebrae), by standing on its hind limbs the torso + neck could be elevated.

Figure 1. Diplodocus standing in a typical feeding posture, as in its prosauropod ancestors.

Figure 1. Diplodocus standing in a typical feeding posture, as in its prosauropod ancestors. Diplodocus could potentially increase its feeding height up to about 11m

Wikipedia reports,
“No skull has ever been found that can be confidently said to belong to Diplodocus, though skulls of other diplodocids closely related to Diplodocus are well known.”

Figure 2. Diplodocus skull animation. Note the short chin and voluminous throat.

Figure 2. Diplodocus skull (USNM 2672, CM 11161) animation. Note the short chin and voluminous throat.

The peg-like teeth of Diplodocus
were smaller and fewer than in other sauropods. And the skull was smaller with nares placed higher on the skull. Evidently diplodocids could only handle smaller needles and leaves from conifer trees matching their height. Wikipedia reports, “Unilateral branch stripping is the most likely feeding behavior of Diplodocus.”

Figure 4. Subset of the LRT focusing on the Phytodinosauria. Three sauropods are added here.

Figure 4. Subset of the LRT focusing on the Phytodinosauria. Three sauropods are added here.

We know of junior diplodocids
(Fig. 5), half the skull length but with relatively larger eyes. Cute!

Figure 5. A small Diplodocus skull to scale with an adult one.

Figure 5. A small Diplodocus skull to scale with an adult one.

References
Marsh OC 1878. Principal characters of American Jurassic dinosaurs. Part I. American Journal of Science. 3: 411–416.